Fuel pump



Patented Aug. 1, 1944 Miamisburg, Ohio, assignors to General Motors Mich., a corporation of Corporation, Detroit Delaware Application January 25, 1943, Serial No. 473,484

2 Claims.

Numerous suggestions have been made which aim to improve the delivery of fuel from a tank to an engine, especially for motor vehicleuse. In accordance with the more common practice a pump is driven by the engine. Its suction stroke draws fuel from the tank and its discharge stroke supplies the carburetor. Such supply systems, while generally satisfactory, have certain inherent disadvantages. The pump does not begin to operate until the engine is started. The suction tends, under adverse conditions, to vaporize the liquid fuel and cause vapor lock. The pump is located adjacent the engine where it is subject to the engine heat. To overcome these and other disadvantages it has been proposed to use an electrically operated pump within the tank. In this way the pump starts its operation when the battery current is supplied, as by turning the ignition switch. It does not wait for the engine to start. The liquid fuel is forced under pressure from the tank to the engine whereby vapor lock is prevented.

It is within the field of this newer development that this invention belongs. By the use of an electric motor and a pump within the fuel tank the above objects and advantages are attained. It has for a further object the simplification of such a pumping assembly whereby a smaller pump and motor is made possible and wherein the conventional form of bypass may be omitted. These and other objects and advantages will be understood from the description which follows: I

In the drawing:

Figure 1 is a transverse section through a tank equipped with a motor and pump.

7 Figure 2 is a section on line 22 of Figure 1. Figure 3 is a section on line 33 of Figure 2. Numeral 5 is used on the drawing to designate the fuel tank. It may be assumed to be the conventional tank of a motor vehicle located at some distance from the engine. The tank has an opening in its upper surface as at l. A base or support 9 rests on the top of the tank and has a locating flange ll entering the opening I. A

ring I3 within the tank and around the opening I is used to cooperate with any convenient fastening means to secure the base 9 in position.

Any suitable bracket means such as [5 is carried by the support 9 for mounting an electric motor 11, fastening means being shown at l9. Numeral 2| represents the leads for the motor. The

motor shaft 23 is coupled at 25 to a shaft 21 which is journaled in the base 9 and passes through a packing 29. A cover 3| secured to the base at 33 serves as a motor housing.

Within the tank the base 9 is extended as a hollow tube 35. Its lower end is near the bottom wall of the tank. The bore is enlarged from a point marked 3'! to the end and into the enlarged bore is fitted a venturi 39 of known form. The lower end of the venturi is spaced slightly from the end of the bore. At the lower end of the tube 35 its wall is enlarged as at 4| to journal at 43 a spindle 45 of a pump rotor ll. The beforementioned shaft 21 is drivingly associated with the spindle 45 as at 49. Beneath the lower end of the tube 35 and its enlargement 4| is a block 5| surrounded by a screen 53. An end cap completes the assembly. The block 51 has an opening 51 leading to a pump chamber 59 which is so located as to be eccentric in its relation to rotor 41. The rotor is provided with vanes 6| whereby there is formed a vane pump. The pump receives fuel from the tank through screen 53 and inlet 51 and delivers it through an outlet passage 63 and into a chamber 65 both formed in the block. A jet 61 leads from chamber 65 to the space immediately beneath the venturi, the jet and the venturi being coaxial. Passages 69 are also formed in the block leading to the space beneath the venturi and above the jet.

At the top of the tank the base is formed with a passage H communicating with the bore of tube 35. A pipe 13 is connected to the passage II by suitable fittings such as 15. Pipe 13 is to supply a conventional carburetor in the embodiment being described.

When the battery circuit through the motor ll is closed the pump is immediately driven. It does not wait for the engine to start. Fuel is taken from the tank through opening Bl. The pump delivers the fuel through the jet 61. The discharge through the venturi causes a low pressure high speed flow through the constricted region whereby additional fuel is drawn through passages 69 to the venturi. This fuel flow supplies the engine through tube 35 and pipe 73. Since more fuel is supplied to the engine than that delivered by the pump the capacity of the pump need not be so great as would otherwise be necessary. As pressure builds up in the tube 35, it checks the quantity flowing in through passages 69. If the carburetor valve closes completely while the pump is still operating there is a reverse fiow through passages 69 to the tank.

The arrangement described delivers fuel from the tank under positive pressure instead of by suction, thus avoiding vapor lock. The pump starts as soon as the electric circuit through the motor is closed. The venturi, serving as a booster, makes possible a relatively small pump which requires but a small motor. The need for a conventional by-pass such as is used With similarly located and driven pumps is avoided by the-provision for reverse flow through passages 69."

It may be said that this invention is related to others such as that shown in Serial No. 456,797 assigned to the assignee of this application. and in which a venturi has been incorporated in a closed system. It is believed that this simplified form may be regarded as a, progressive step in the development of this sort of fuel supply. In practice it may be found desirable to employ a check valve in the conduit to the carburetor to prevent syphoning back to the tank.

f duit means leading from the tank" to the region between the jet'and venturi.

2. In a fuel supply system, a fuel tank, a, pump near the bottom of the tank, motor means to drive the pump, means forming a jet through which the pumped fuel passes, a venturi coaxial with and above the jet, conduit means adapted to con- 'vey fuel from the venturi, and other conduit 

